Theoretical study of hydrogen impact on concentration of intrinsic point defects during Czochralski Si crystal growth
Theoretical study of hydrogen impact on concentration of intrinsic point defects during Czochralski Si crystal growth
复制标题
DOI：
10.1016/j.jcrysgro.2020.125971
复制
发表时间：
2021-02-01
影响因子：
1.8
通讯作者：
Hourai, Masataka
中科院分区：
文献类型：
--
作者：
Kusunoki, Takuya;Sueoka, Koji;Hourai, Masataka
为了满足最新半导体器件的性能要求，硅衬底需要在原子水平上控制本征点缺陷(空位V和间隙硅)。Sugimura等人。(2014)最近报道，在直拉硅单晶生长过程中掺入氢原子对点缺陷行为有两方面的影响：(I)硅晶体变得更富V和(Ii)位错团簇的形成被抑制。(II)的发现表明，氢掺杂是一种很有前途的技术，可以大规模生产用于功率器件的硅衬底，以及其他应用。然而，在硅单晶生长过程中，氢掺杂对点缺陷行为的影响还不是很清楚。本研究的目的是澄清(I)的结论。我们用第一性原理计算了由原子和216Si原子组成的超晶胞中H原子影响区域内V和I的形成能和形成(振动)熵，并在此基础上得到了熔体/固体界面上的点缺陷浓度。我们的主要发现如下。(1)有三种结构的氢空位复合体(H-V)和四种结构的氢-间隙硅复合体(H-I)，其中V的形成能显著降低；(2)H对V浓度的影响大于对I浓度的影响，当H浓度大于10(15)/cm(3)时，H对V浓度的影响更为明显。(3)定量解释了H对本征点缺陷浓度影响的实验结果。
Control of intrinsic point defects (vacancy V and interstitial Si I) at the atomic level is required for Si substrates to satisfy the performance demands of the latest semiconductor devices. Sugimura et al. (2014) recently reported that doping hydrogen (H) atoms during Czochralski Si crystal growth affects the point defect behavior in two ways: (i) Si crystal becomes more V rich and (ii) the formation of dislocation clusters is suppressed. The finding of (ii) suggests that H-doping is a promising technique for the mass production of Si substrates used for power devices, among other applications. However, the effect of H-doping on point defect behavior during Si crystal growth is not yet fully understood. The purpose of the present study is to clarify the finding of (i). We performed first principles calculation of the formation energy and formation (vibration) entropy of V and I in the area influenced by the H atom in supercells composed of 64 and 216 Si atoms and then obtained the concentration of point defects incorporated at the melt/solid interface on the basis of the results. Our main findings are as follows. (1) There are three structures of hydrogen-vacancy complex (H-V) where the V formation energy remarkably decreases and four structures of hydrogen-interstitial Si complex (H-I) where the I formation energy remarkably decreases. (2) The H impact on V concentration is larger than that on I concentration and becomes apparent when H concentration is higher than 10(15)/cm(3). (3) The experimental finding of H impact on the concentration of intrinsic point defects is explained quantitatively.